Apparatus for winding a coil assembly



March 23, 1965 M. sclAKY APPARATUS FOR WINDING A COIL ASSEMBLY 6 Sheets-Sheet l Filed Nov. 3, 1961 March 23, 1965 M. sclAKY APPARATUS FOR wINDING A conJ ASSEMBLY 6 Sheets-Sheet. 2

Filed NOV- 5, 1961 March 23, i965 M. sclAKY 3,174,699

APPARATUS FOR WINDING A COIL ASSEMBLY Filed Nov. 5, 1961 6 Sheets-Sheet 3 March 23, 1965 M. sclAKY 3,174,699

APPARATUS FOR WINDING A COIL ASSEMBLY Filed Nov. 3, 1961 6 Sheets-Sheet 4 March 23, 1965 M. scIAKY 3,174,699v

APPARATUS FOR WINDING A COIL ASSEMBLY Filed Nov. 5, 1961 6 Sheets-Sheet 5 March 23, 1965 M. sclAKY 3,174,699

APPARATUS FDR WINDING A COIL. ASSEMBLY Filed Nov. 5, 1961 6 Sheets-Sheet 6 iw'o 6am@ @Mwewy-M 9%??- United States Pater Mice 3,174,699 v APPARATUS FR WNEHNG A CGIL ASSEMBL( Mario Seiahy, Saint Cloud, France, assigner to Welding Research, Inc., Qhicago, iii., a corporation of illinois Filed Nov. 3, 195i, Ser. No. 150,@22 2 Claims. (Cl. 242-9) The invention relates to an apparatus for winding sheet etal around a tube in order to form a magnetic circuit for transformers and the like. More particularly the in- Vention has for its object the winding of sheet metal in a manner to produce coil assemblies with wound magnetic cores in one operation, whereas in known methods at least tive successive operations have been required.

The winding of magnetic cores by coiling a strip of sheet metal around a mandrel has been in use and is well known. However, in these methods the mounting of the wire coils is possible only after the magnetic circuit had been constructed. In spite of many complications the technique has been perfected and does not offer any particular difiiculty.

It may also be observed that the method of winding magnetic Cores from sheet metal strip can be preformed in a convenient manner and thus the method is more advantageous than that which consisted in cutting the sheet metal and assembling the cut strips by interleaving. If annealing of grain-oriented sheet metal is indispensable, it is not necessary for silicon sheet metal. However, it has been required up to the present time to maintain this operation in order to eliminate the stress on the sheet metal which has a tendency to open the magnetic circuit. It is therefore seen that with the methods as heretofore employed, the following operations were necessary. Winding of the magnetic cores on a mandrel; annealing; varnishing; cutting; mounting the wire coils on the transformer and attaching the same by means of clamping rings.

The purpose of the present invention is to eliminate the inconveniences by eliminating a large number of the operations although still obtaining a high-quality product.

Another object of the invention is to provide apparatus for producing coil .assemblies with wound magnetic cores and wherein said aparatus produces rotation of the tube which is mounted on the sides of the coils that receive the Wound magnetic circuit, the sheet metal strip being secured to the tube for winding thereon and which remains xed with respect to the coils.

A more specic object of the invention is to provide apparatus for winding relatively thin sheet metal or wire around coil assemblies, said 4apparatus incorporating means for displacing the sheet metal or wire axially during its winding in order to obtain a helical winding.

The machines to wind sheet metal around coil assemblies according tothe invention are shown as examples on the attached drawings in which:

FIGURE l shows a coil assembly with two wound magnetic circuits according to the method of the invention;

FIGURE 2 represents the method of winding of the sheet metal around one of the sides of the coil;

FIGURE 3 represents schematically the machine to obtain wound magnetic circuits according to the method of the invention;

FIGURES 4 and 5 represent schematically a second method employing a driving device for rotating the tube mounted around the coils which receive the wound magnetic circuit; and

FIGURE 6 represents the machine used to coil the magnetic circuit according to the method described in FIG- URES l, 2 and 3, and completed by a device which produces a helical winding of the sheet metal or wire.

According to the method of the invention, the sheet E'MQ Patented Mar. 23, i965 metal which forms the magnetic circuit is wound directly on the coil assembly such as the coils of a transformer, and the sheet metal is terminated by means of a few spot Welds.

To simplify the description, one assumes as an example that the coil assembly I of the transformer has been molded and the two coil elements which will be inside the magnetic circuit have the form of a cylinder d, see FIG- URE l.

Part I shown in full line on FIGURE l contains the primary and secondary coils encased in resin in order to obtain a compact unit which does not necessitate a device to maintain in place the elements of the transformer. The primary connections are at 2 and the secondary connections are at 3. The sheet metal of the magnetic circuit shown in dotted lines at 5 and 6 must be wound around columns d.

According to the method of the invention, see FIGURE 2, around each column 4 is mounted a tube 7 which consists of two half cylinders made of 2 or 3 mm. thick sheet metal. In one of them is welded the edge of the sheet metal strip to be wound. The tube 7 is then made to rotate and the sheet metal is wound around the tube. When the desired winding diameter is reached, it is sucient to terminate the sheet metal with a few spot welds and to cut the strip. The metal tube 7 remains in place on the column 4 and becomes part of the core structure.

The above method presents several advantages particularly a reduction to one operation of the live operations which are necessary in the known processes described above. Particularly, the cutting is eliminated, which in spite of all precautions may short circuit the neighboring laminations and increase the eddy current losses.

FIGURES 2 and 3 represent a machine which will operate to perform the above method. In FIGURE 2 one of the magnetic circuits 5 has been shown in full line wound around column 4 of the coil assembly 1 and the second magnetic circuit 6 which will be wound later is shown in dotted lines. On each end of tube '7 surrounding column i are mounted wheels S and 9 which are cut along a diameter and which are assembled by an appro priate device. Each wheel contains a smooth rim 15 and gear teeth I6. The two wheels roll on three rollers itil, i102 and 193 which contain a throat I7 which centers the part and gear teeth 13 through which the part is driven.

FIGURE 3 shows a cross section of the profile of the machine. Sheet metal Il passes through three rollers I2, 13 and lid, arranged in a manner which pre-forms the sheet metal and simplifies its winding. One of the wheels 9 is also shown rolling on the three rollers lill, 102 and 163, as Well as cylinder 7. The second magnetic circuit 6 is also obtained in the same manner.

In order to make the drawing of FIGURE 2 readable, a certain distance was provided between the magnetic circuit S and the end of the coil assembly ll. In practice, this distance will be reduced as much as possible by using wheels 8 and 9 as narrow as can be produced. Various modiiications can be made to the above described machine without going out of the range of the invention.

FIGURES 4 and 5 represent another modification of a device which rotates the tube 7, which is mounted around the coils which receive the wound magnetic circuit. Tube '7 is supported by several lines of rollers 2i) which are rubber covered for example, to obtain a large coeihcient of adherence. On FIGURES 4 and 5, four lines of rollers Ztl are shown. At least one 4of these rollers is a motor. According to the results that one wishes to obtain, the speeds of the other rollers which are driven could be established at a desirable ratio. Each line of rollers 26 is supported by an arm 21 which pivots on a support 22. The arms 2l of each line of rollers are coupled to each other by coupling rods 23 so that the center of rotation of the assembly remains xed. Piston 25 which slides in anvair-compressed cylinder 24 is coupled to one of the levers 21 by the rod 26 in' order that the rollers are pressed under air on the sheet metal 11 which is wound around tube 7.

Another Way to realize this machine is shown in FIG- URE 6. This machine can produce a magnetic circuit with a strip of small width or with wire. This may be necessary for various reasons and particularly when the transformer will operate at high frequency. This machine is shown schematically on FIGURE 6 and to simplify its description, the front part of the coil assembly 1 has been removed. This machine, similar to that described previously in FIGURE 3, contains in addition a moving roller 32 which guides the narrow strip 30 in order to obtain a helical winding. This roller, whose throats are at a distance equal to the width of the strip, rotates freely on axle 33 but does not slide on this axle.

Axle 33 goes through two supports 31 and 34 which guide this axle. The support 31 contains a mechanism which insures the axial displacement of axle 33. This translation movement can be adjusted in order to obtain a winding pitch equal to the width of the strip. The drive of the control device of the support 31 is joined to the rotation movement of the wheels 10. Although the diameter of the magnetic circuit 5 increases progressively, the pitch remains constant and it is sufficient that the displacement of axle 33 be joined in a constant ratio with the rotation of Wheel 9. This ratio is such that one revolution of the wheel 9 causes a displacement of axle 33 equal to the Width of the strip.

The support 31 also contains a system which reverses the direction of displacement of axle 33 when the strip 30 has been displaced until it reaches one of the gears 8 or 9. It is evident that the invention is not limited to the examples described and represented above trom which other forms of realization can be obtained without going outside the range of the invention.

What is claimed is:

1. In apparatus for winding a strip of sheet metal around the cylindrical part of a coil assembly, whereby to form a metal core for the assembly, in combination, a metal tube having a concentric encircling relation with the cylindrical part, said metal tube consisting of two 10ngitudinal half sections, whereby to facilitate the placing of the tube around the cylindrical part of the coil assembly, one end of said sheet metal strip being secured to one of the half sections of the tube, at least one gear wheel releasably fixed to an end of the tube, and driving means for rotating the tube including a pinion gear having meshing relation with the gear wheel.

2. Apparatus for winding a strip of sheet metal around the cylindrical part of a coil assembly as dened by claim l, wherein the gear wheel is sectional along a diameter to permit the xing of the gear Wheel to an end of the tube in concentric relation therewith and its subsequent release from said tube.

References Cited by the Examiner UNITED STATES PATENTS 2,246,239 6/41 Brand 29-l55.57 2,305,999 12/ 42 Steinmayer et al 242-4 2,324,115 7/42 Schultz '29-15557 2,334,131 11/'43 Schultz 242-4 2,366,977 l/ Morrison 242-4 2,915,811 12/59 Zach et al. 29-155-57 2,929,132 3/60 Wohlhieter 29-l55.57 3,043,000 7/62 Hatfield 242-4 X MERVIN STEIN, Primary Examiner.

WHITMGRE A.WILTZ, RUSSELL C. MADER,

Examiners. 

1. IN APPARATUS FOR WINDING A STRIP OF SHEET METAL AROUND THE CYLINDRICAL PART OF A COIL ASSEMBLY, WHEREBY TO FORM A METAL CORE FOR THE ASSEMBLY, IN COMBINATION, A METAL TUBE HAVING A CONCENTRIC ENCIRCLING RELATION WITH THE CYLINDRICAL PART, SAID METAL TUBE CONSISTING OF TWO LONGITUDINAL HALF SECTIONS, WHEREBY TO FACILITATE THE PLACING OF THE TUBE AROUND THE CYLINDRICAL PART OF THE COIL ASSEMBLY, ONE END OF SAID SHEET METAL STRIP BEING SECURED TO ONE OF THE HALF SECTIONS OF THE TUBE, AT LEAST ONE GEAR WHEEL RELEASABLY FIXED TO AN END OF THE TUBE, AND DRIVING MEANS FOR ROTATING THE TUBE INCLUDING A PINION GEAR HAVING MESHING RELATION WITH THE GEAR WHEEL. 